Physical Property Data and Estimates

Knowledge of physical properties is essential for the design of innovative chemical products and processes. It would be very difficult to select a pump without knowing the liquid's density and viscosity, or design a distillation column without knowing component vapor pressures and activity coefficients, or a coating without understanding the mixture's viscosity.

Very often, especially in those early conceptual stages of a new process or product design, we may not know the physical properties of the chemicals and mixtures we are working with. This is when physical property estimation can be very useful. Often from only the knowledge of a chemical's molecular structure or a mixture's component, we can use estimation techniques to obtain a good estimates, good enough for our design calculations.

If you are searching for physical property data and estimates, visit the web pages listed to the right. The "Data and Estimates" page contains data on more than 2,000 chemicals. This web page also provides you with estimates as functions of temperature and pressure. The "Introduction" page enables you to draw the molecular structure of a chemical and estimate its physical properties using group-contribution and equation-based techniques.

If you are interested in learning more about any particular estimation techniques, e.g., learning about how accurate a technique might be, click on a technique name below. The technique's webpage will provide you with background information, error estimates, and the ability to use an online version of the technique.

Finally, if you have any suggestions for additional data or techniques, or any general suggestions, comments, or questions, please contact us. We are also happy to talk about physical properties.

Thank you, Kevin G. Joback
Molecular Knowledge Systems, Inc.

Chemicals: Physical Property Data and Estimates
This webpage provides with physical property data and estimates for more than 2,000 chemicals. If needed, you may enter a range of temperatures and/or pressures at which you need properties determined. Data and estimates are presented in both tabular and graphical formats. An introductory video is provided below. Visit the webpage by
clicking here.
Molecular Structure: Physical Property Estimates
This webpage enables you to draw a chemical's molecular structure and have more than 30 physical properties estimated. The webpage uses both group-contribution and equation-based estimation techniques. We hope that the webpage also provides a good introduction to the field of physical property estimation. An introductory video is provided below. Visit the webpage by
clicking here.
Export Physical Properties to Chemical Software Tools
If you need physical properties for use in other software tools, e.g., ASPEN, CHEMCAD, MATLAB, you can use one of the exporters listed below. On these webpages, you draw a molecular structure and then generate a physical property input file that can be downloaded and imported into your software tool.
Estimation Techniques

We are continually adding new estimation techniques to both Cranium and Synapse. Below is a listing of the current techniques included in the MKS Core Knowledge Base. Click on the technique's name to see more details including implementation notes and evaluation statistics. (As always, please contact us to request the addition of new techniques.)

Autoignition Temperature
Critical Compressibility
Critical Temperature - f(X)
Diffusion Coefficient, Liquid - f(T,X)
Diffusion Coefficient, Vapor - f(T,P,X)
Enthalpy of Combustion at 298K
Enthalpy of Formation, Liquid at 298K
Enthalpy of Formation, Liquid at 298K
Enthalpy of Fusion at Tm
Enthalpy, Liquid - f(T)
Enthalpy, Liquid - f(T,P)
Enthalpy, Vapor - f(T)
Entropy, Liquid - f(T)
Entropy, Vapor - f(T)
Flammability Limit, Lower - f(X)
Flammability Limit, Upper
Flammability Limit, Upper - f(X)
Fugacity Coefficient, Liquid - f(T,P)
Fugacity Coefficient, Liquid - f(T,P,X)
Fugacity Coefficient, Vapor - f(T,P)
Fugacity Coefficient, Vapor - f(T,P,X)
Gibbs Energy of Formation, Liquid at 298K
Gibbs Energy of Formation, Solid at 298K
Gibbs Energy of Formation, Vapor at 298K
Heat Capacity - Isobaric, Liquid - f(T,X)
Heat Capacity - Isobaric, Liquid at 298K
Heat Capacity - Isobaric, Solid - f(T)
Heat Capacity - Isobaric, Solid at 298K
Heat Capacity - Isobaric, Vapor - f(T)
Heat Capacity - Isobaric, Vapor - f(T,X)
Heat Capacity - Isobaric, Vapor at 298K
Heat Capacity - Isometric, Vapor - f(T)
Henry's Constant (pc) in H2O - f(T)
LC50 96hr, Fathead Minnow
Molecular Weight
Molecular Weight - f(X)
Refractive Index, Liquid at 293K
Relative Permittivity, Liquid - f(T)
Relative Permittivity, Liquid - f(T,X)
SLE, Liquidus Temperature - f(P,X)
Second Virial Coefficient - f(T)
Solubility Parameter, Dispersive
Solubility Parameter, Dispersive - f(X)
Solubility Parameter, Hydrogen Bonding
Solubility Parameter, Hydrogen Bonding - f(X)
Solubility Parameter, Polar - f(X)
Speed of Sound, Liquid - f(T)
Speed of Sound, Vapor - f(T,P)
Surface Tension, Liquid - f(T,X)
Thermal Conductivity, Vapor - f(T,P)
Viscosity, Liquid - f(T,P)
Viscosity, Vapor - f(T,P)
Viscosity, Vapor - f(T,X)
log(Octanol/Water Partition Coefficient)